Ratajczak-Wielgomas et al. showed that benign lesions of the breast showed no stromal PON deposition, whereas PON was deposited around malignant mammary ducts in ductal carcinoma in situ, and was more widely deposited in the cancer stroma of invasive ductal carcinoma of the breast, particularly in cases showing high-grade histological atypia [19]. The gene discussed is PON1; the disease is ductal breast carcinoma in situ.